Problem destroying cloned prefabs

I instantiate a lot bat prefab from within a coroutine. Each prefab has a touch detection which should destroy the clone on touch.

My problem now, is that all clones a destroyed at once, if I touch a prefab. And not only the one that got touched.

this is the script which generates the bat prefabs:

 public class BatGenerator : MonoBehaviour {
 
     public GameObject Bat;
     public GameObject CountDown;
     private GameObject Main;
 
     private int CountDownTimer;
     private bool GameDone;
     private bool BatGeneratorRunning;
     private int BatCounter;
 
     // Use this for initialization
     void Start () {
         GameDone = false;
         Main = GameObject.Find("Main");
         BatGeneratorRunning = false;
         BatCounter = 1;
     }
 
     void Update()
     {
         CountDownTimer = Convert.ToInt32(CountDown.GetComponent<Text>().text);
         
         if (Main.GetComponent<SchreiGameEvents>().GameRunning && !BatGeneratorRunning)
         {
             BatGeneratorRunning = true;
             Debug.Log("Start Coroutine");
             StartCoroutine("GenerateBat");
             
         }
 
         if (GameDone)
         {
             Application.LoadLevel("GameScene");
         }
 
     }
 
     IEnumerator GenerateBat()
     {
         CountDownTimer = Convert.ToInt32(CountDown.GetComponent<Text>().text);
 
         while (CountDownTimer > 0)
         {
             CountDownTimer = Convert.ToInt32(CountDown.GetComponent<Text>().text);
             Vector3 BatPos = new Vector3(UnityEngine.Random.Range(-6f, 6f), UnityEngine.Random.Range(-0.7f, 3.36f), 0);
             GameObject clone = (GameObject)Instantiate(Bat, BatPos, Quaternion.identity);
             clone.name = "Bat_" + BatCounter;
             Animator BatAnimator = clone.GetComponent<Animator>();
           
             BatAnimator.Play("BatFly");
             yield return new WaitForSeconds(0.6f);
             BatCounter++;
         }
         GameDone = true;
        
         yield return null;
         
     }
 }

And this is my AI script on each prefab to detect the touch event and destroy the clone:

 public class BatAI : MonoBehaviour
 {
     private GameObject BatHitCounter;
     private int killedBats;
     private bool alreadyHit;
     private Vector3 lastScale;
     public Animator BatAnimator;
    
 
     public AudioClip BatSwatter;
     private GameObject Main;
     private bool BatAnimationRunning;
     private RuntimePlatform platform;
 
 
     void Start()
     {
         BatHitCounter = GameObject.Find("batHitCounter");
         Main = GameObject.Find("Main");
         BatAnimationRunning = false;
         platform = Application.platform;
         alreadyHit = false;
     }
 
     // Update is called once per frame
     void Update () {
 
         if (Main.GetComponent<SchreiGameEvents>().GameRunning && !BatAnimationRunning)
         {
             BatAnimationRunning = true;
             this.BatAnimator.Play("BatFly");
         }
         if (Main.GetComponent<SchreiGameEvents>().GameRunning)
         { 
             if (this.transform.localScale.x >= 0.59f && !alreadyHit)
             {
                 
                 BatAnimator.SetTrigger("MaxSizeReached");
                 Destroy(this.gameObject);
                
             }
         }
         if (platform == RuntimePlatform.Android || platform == RuntimePlatform.IPhonePlayer)
         {
             if (Input.touchCount > 0)
             {
                 if (Input.GetTouch(0).phase == TouchPhase.Began)
                 {
                     checkTouch(Input.GetTouch(0).position);
                 }
             }
         }
         else if (platform == RuntimePlatform.WindowsEditor)
         {
             if (Input.GetMouseButtonDown(0))
             {
                 checkTouch(Input.mousePosition);
             }
         }
 
     }
 
     private void checkTouch(Vector3 pos)
     {
          Vector3 wp = Camera.main.ScreenToWorldPoint(pos);
          Vector2 touchPos = new Vector2(wp.x, wp.y);
          Collider2D hit = Physics2D.OverlapPoint(touchPos);
      
          if(hit)
          {
              Debug.Log(hit.transform.gameObject.name);
              //hit.transform.gameObject.SendMessage('Clicked',0,SendMessageOptions.DontRequireReceiver);
              lastScale = this.transform.localScale;
              alreadyHit = true;
              Debug.Log("Hit");
              BatAnimator.SetTrigger("Hit");
              this.transform.localScale = lastScale;
              StartCoroutine(DestroyBat(hit));
          }
     }
     
     IEnumerator DestroyBat(Collider2D hit)
     {
         SoundManager.instance.PlaySingle(BatSwatter);
         killedBats = Convert.ToInt32(BatHitCounter.GetComponent<Text>().text);
         BatHitCounter.GetComponent<Text>().text = (killedBats+1).ToString();
         yield return new WaitForSeconds(0.4f);
         BatAnimator.SetTrigger("Dead");
 
         Destroy(this.gameObject);
     }
    
 }

  

I hope you can help me with that problem.

Thanks in advance Frank